This invention relates to minimum tillage agricultural implements having furrow opening shank assemblies for forming narrow furrows and depositing or xe2x80x9cshankingxe2x80x9d fertilizer and or seeds therein in soil that is overburdened with agricultural residue.
Even though the advantages of minimum tillage agricultural practices in arid and semi-arid soils have been known for some time, their adoption has been rather slow.
One of the problem s has been the difficulty associated with providing efficient high speed implements that are capable of placing or xe2x80x9cshankingxe2x80x9d fertilizer and/or seeds in the soil with uniform precision when the soil is overburdened with a substantial mat or layer of agricultural residue. Often the residue will bunch, pile or xe2x80x9chair pinxe2x80x9d against the furrow opening shanks requiring the implement to either be slowed down or stopped and the built-up residue removed by the operator from in front of the shank. The problem becomes even more difficult when the residue is either wet or quite dense or quite thick. Because of these problems the implements used require application methods that result in higher soil disturbance not conducive to minimum tillage procedures.
Furthermore, to accommodate the residue overburden, the shanks must be taller and spaced further apart, both side-to-side on the same tool bar and front-to-back on multiple tool bars. The side-to-side limitation increases the distances between crop rows per tool bar, requiring more tool bars. The more front-to-back tool bars increases the problems associated with turning the implement at the end of the rows. Often when the implement is turned on a corner or on a side hill the shanks on one tool bar will line up with the shanks on another tool bar resulting in uneven row spacing and inefficient or duplicate application of fertilizer. Additionally, the more tool bars substantially increases the implement framework required to support the increased number of tool bars, thereby substantially increasing the cost of the implement.
Considerable effort has been expended in providing rather expensive devices, called xe2x80x9ccoultersxe2x80x9d, forward of the shanks for cutting or slicing through the residue to minimize the bunching up or xe2x80x9chair pinningxe2x80x9d of the residue on the front of the shanks. One such design is illustrated in U.S. Pat. No. 4,762,075 issued Aug. 9, 1988 to James W. Halford entitled xe2x80x9cSeed/Fertilizer Minimum Tillage Planterxe2x80x9d. FIGS. 1-4 of the Halford patent show a xe2x80x9ccoulterxe2x80x9d design and FIGS. 5-9 show a non-coulter design that has deflector plates 141 mounted to the shank 15 that extend rearward and outward from the front edge of the shank to deflect trash laterally and rearward away from the shank 15. Such a design has the disadvantage of also deflecting some of the soil uprooted by the shank away from the shank, effectively widening the furrow and compromising the minimum tillage procedure. There are many other patents that show various xe2x80x9ccoulterxe2x80x9d and xe2x80x9cnon-coulterxe2x80x9d designs that are classified in Class 111 of the U.S. Patent Classification System.
The principal object of the present invention is to provide a substantially improved relatively high speed minimum tillage agricultural implement having furrow opening shank assemblies that are more efficient in xe2x80x9cshankingxe2x80x9d fertilizers or seeds into soils having substantial agricultural residue overburdens.